Machining facility using sub-pallet

ABSTRACT

Provided is a flexible machining facility using a sub-pallet, which can quickly satisfy the increasing or decreasing of units or other required specifications. It The machining facility includes a machine tool ( 1 ) having a pallet changer ( 47 ) for changing main pallets ( 39 ), a plurality of sub-pallets ( 3 ) for a workpiece to be mounted thereon, a setup station ( 5 ) for carrying the sub-pallet ( 3 ) and mounting and dismounting a workpiece on and from the sub-pallet ( 3 ), a sub-pallet stocker ( 7 ) for carrying the sub-pallet ( 3 ) thereon, and a sub-pallet conveyor system ( 9 ) for conveying the sub-pallet ( 3 ) and configured to include sub-pallet carrying parts of the machine tool ( 1 ), setup station ( 5 ), and sub-pallet stocker ( 7 ) in a workable area thereof. The sub-pallet ( 3 ) can be used to convey and machine a workpiece.

TECHNICAL FIELD

The present invention relates to a machining facility which has asub-pallet for mounting a workpiece thereon and conveys the sub-palletbetween units provided with sub-pallet carrying parts.

The “units” in the specification refer to the machine tools, setupstation, sub-pallet stockers, cleaning station, inspection station, andother main components forming a part of a machining facility. Further, a“main pallet” refers to a pallet which is detachably mounted on a palletmounting table of a machine tool by a pallet changer. This main palletis sometimes also provided with a mounting fixture such as an angleplate or a rotary cable. A “sub-pallet” is a pallet on which a workpieceis mounted and which is detachably mounted on a sub-pallet carrying partof a main pallet or a mounting fixture such as an angle plate or rotarytable provided on a main pallet.

BACKGROUND ART

A machining facility called a “machining system” or a “machining cell”is a system for conveying and changing workpieces between at least onemachine tool, such as machining center, lathe, grinding machine orelectro-discharge machine, and a workpiece placing location called a“setup station” or “stocker” so as to facilitate machining ofworkpieces. There is the method of using a robot or a manipulator todirectly convey workpieces or convey pallets having workpieces mountedthereon.

Japanese unexamined Parent Publication No. 59-107833 discloses ahandling robot which loads and unloads a workpiece between a spindle ofa lathe and a conveyor unit and performs the loading and unloading ofthe workpiece on and from the lathe automatically.

Japanese Patent Publication (B2) No. 3-51545 discloses a palletconveying robot which conveys a pallet having a workpiece mountedthereon between a workpiece station and a table of a machine tool. Inthe past, a robot having one arm was used to grip an old pallet mountedon a table of a machine tool and convey it to a workpiece station, thengrip a new pallet on the workpiece station and convey and mount it tothe table of the machine tool. Therefore, the conveyance efficiency waspoor. However, this invention solves this problem and enables aplurality of pallets to be efficiently conveyed.

Japanese Utility Model Publication No. 5-46834 discloses a setup systemfor enabling a sub-pallet having a workpiece mounted thereon to beautomatically mounted and dismounted on and from a main pallet andfeeding and discharging workpieces to a main pallet conveyor system. Inthe past, a workpiece was mounted and dismounted on and from an angleplate on a main pallet, and therefore the efficiency of the setup workwas poor. However, this invention solves this problem and enablesworkpieces set-up in advance to be automatically mounted on angle platesin the setup station and thereby improves the work efficiency.

In the prior art described in Japanese Unexamined Patent Publication No.59-107839, the body of a handling robot is fixed to a base of a latheand the motion of the arm about three rotational axes and the motionalong one linear movement axis can be used to convey and mount aworkpiece, placed on a conveyor unit facing upward, on a horizontallyoriented spindle of the lathe while changing the direction. Further, itis possible to reverse the orientation of the workpiece and mount it onthe spindle. At the front end of the arm, it is possible to detachablymount two or more types of hands which can be changed according to theshape and weight of the workplaces. In this mode, since the workpiece isdirectly gripped by the robot hand and workpieces come in various shapesand sizes, it is necessary to change two or more types of hands.Therefore, there is the problem that it is necessary to prepare aplurality of hands and prepare a plurality of hand operating programs.

The pallet conveying robot of the prior art described in Japanese PatentPublication (B2) No. 3-51545 has a swiveling member, rotating member,sliding member, and a pair of independently swivelable arms (first armand second arm). It discloses a configuration wherein motion about fourrotational axes and motion along one linear movement axis are used togrip a pallet of a workpiece station placed in a state with theworkpiece mounting surface of the pallet facing upward by one arm, gripa pallet mounted on the table of the machine tool in a state with theworkpiece mounting surface of the pallet facing sideways by the otherarm, simultaneously convey the two pallets while changing theorientations of the pallets, and then change the pallets. This palletconveying robot conveys a pallet to be mounted and dismounted on andfrom a table of a machine tool, that is, a main pallet, and theworkpieces are directly mounted on the main pallets. When a main palletis large in size or when a main pallet has an angle plate or rotarytable mounted on it, even if the workpiece is small in size, the weightconveyed by the robot becomes larger. This being the case, there is theproblem that the conveying robot also becomes larger in size.

The prior art described in Japanese Utility Model Publication No.5-46834 is configured by providing a setup station, which can convey,invert, and rock a main pallet, between a main pallet conveyor system(pallet pool line) attached to a machine tool and a sub-pallet conveyorsystem making a sub-pallet roll and slide in the horizontal statesub-pallet conveyor line). An angle plate is fixed to the main pallet,the sub-pallet mounting surface of the angle plate is matched in heightwith the sub-pallet rolling and sliding surface of the sub-palletconveyor line, and a slide operation is used to dismount an oldsub-pallet from the angle plate and mount a new sub-pallet on the angleplate. The main pallet having a new sub-pallet mounted on the angleplate is then inverted and returned to the pallet pool line. Thisinvention conveys the main pallet to the sub-pallet conveyor line andmounts and dismounts sub-pallets on and from the main pallet. Thisinvention is configured such that the sub-pallet just slides on thesub-pallet conveyor line and a setup system conveys, inverts and rocksthe main pallet in order to mount the sub-pallet on the main pallet.That is, there is the problem that the setup system becomes large insize.

DISCLOSURE OF THE INVENTION

The present invention is directed to solve the problems in the prior artand an object of the present invention is to provide a flexiblemachining facility using a sub-pallet, which can quickly satisfyrequired specifications such as the increasing or decreasing of machinetools, setup stations, sub-pallet stockers, cleaning stations, and otherunits, carry the sub-pallet with the workpiece mounting surface of thesub-pallet facing upward or sideways, and quickly position a sub-palletgripper of a sub-pallet conveyor system and a sub-pallet carrying partof each unit.

Another object thereof is to provide a machining facility using asub-pallet, which can easily remove chips and coolant solution attachedon the sub-pallet or workpiece.

Another object thereof is to provide a machining facility using asub-pallet, which enables fast conveyance of a workpiece and a reductionof size of a conveyor system by conveying a sub-pallet, lighter than amain, pallet rather than conveying a main pallet when mounting anddismounting the sub-pallet for the workpiece to be mounted thereon onand from a machine tool.

To achieve these objects, according to the present invention, there isprovided a machining facility having a sub-pallet for a workpiece to bemounted thereon and conveying the sub-pallet between units provided withsub-pallet carrying parts, which includes: at least one machine toolhaving a pallet changer for changing main pallets; a plurality ofsub-pallets for a workpiece to be mounted thereon, formed no be able tobe mounted on a sub-pallet carrying part provided on said main pallet; asetup station for mounting and dismounting a workpiece on and from saidsub-pallet, the setup station having a sub-pallet carrying part forcarrying the sub-pallet thereon; and a sub-pallet conveyor system forconveying the pallet, the sub-pallet conveyor system configured toinclude the sub-pallet carrying parts of the machine tool and the setupstation in a workable area thereof, wherein the said sub-pallet is usedto convey and machine a workpiece. This machining facility mounts anddismounts the workpiece on and from the sub-pallet at the setup stationand conveys the sub-pallet, by the sub-pallet conveyor system, to themachine tool having the main pallet changer.

Further, according to the present invention, there is provided amachining facility, which further includes a sub-pallet stocker having asub-pallet carrying part for carrying the sub-pallet thereon andinstalled so as to include the sub-pallet carrying part in the workablearea of the sub-pallet conveyor system. This machining facility furtherincludes the sub-pallet stocker as a unit and can load and unload thesub-pallet into and from the sub-pallet stocker by the sub-palletconveyor system.

Further, according to the present invention, there is provided amachining facility, which further includes a cleaning station forremoving chips and coolant solution attached on the sub-pallet and theworkpiece, the cleaning station having a sub-pallet carrying part forcarrying the sub-pallet thereon and installed so as to include thesub-pallet carrying part in the workable area of the sub-pallet conveyorsystem. This machining facility further includes the cleaning station asa unit, and the sub-pallet and workpiece loaded into the cleaningstation are cleaned of the chips and coolant solution.

Further, according to the present invention, there is provided amachining facility, in which said sub-pallet conveyor system has a handfor gripping the sub-pallet. This sub-pallet conveyor system has thehand and uses this hand to grip the sub-pallet.

Further, according to the present invention, there is provided amachining facility having a sub-pallet for a workpiece to be mountedthereon and conveying the sub-pallet between units provided withsub-pallet carrying parts, which includes: at least one machine toolhaving a pallet changer for changing main pallets; a plurality ofsub-pallets for a workpiece to be mounted thereon, formed to be able tobe mounted on a sub-pallet carrying part provided on said main pallets;a setup station for mounting and dismounting a workpiece on and from thesub-pallet, the setup station having a sub-pallet carrying part forcarrying the sub-pallet; a sub-pallet stocker having a sub-palletcarrying part for carrying the sub-pallet thereon and configured tostock the sub-pallet at a slant so that chips and coolant solution will,drop off when the sub-pallet is carried on the sub-pallet stocker; and asub-pallet conveyor system for conveying the sub-pallet, the sub-palletconveyor system having a hand for gripping the sub-pallet and configuredto include the sub-pallet carrying parts of the machine tool, the setupstation and the sub-pallet stocker in a workable area thereof, whereinthe sub-pallet; is used to convey and machine a workpiece. Thissub-pallet stocker is configured to stock the sub-pallet at a slant, andtherefore the chips and coolant sol union attached on the sub-pallet andworkpiece stocked after machined by the machine tool easily drop off.

Further, according to the present invention, there is provided amachining facility having a sub-pallet for a workpiece to be mountedthereon and conveying the sub-pallet between units provided withsub-pallet carrying parts, which includes: at least one machine toolhaving a pallet changer for changing main pallets; a plurality ofsub-pallets for workpieces to be mounted thereon, formed to be able tobe mounted on a sub-pallet carrying part provided on the main pallet; asub-pallet stocker having a sub-pallet carrying part for carrying thesub-pallet thereon and configured to stock the sub-pallet at a slant sothat chips and coolant solution will drop off when the sub-pallet iscarried on the sub-pallet stocker; and a sub-pallet conveyor system forconveying the sub-pallet, the sub-pallet conveyor system having a handfor gripping the sub-pallet and configured to include the sub-palletcarrying parts of the machine tool and the sub-pallet stocker in aworkable area thereof, wherein the sub-pallet is used to convey andmachine a workpiece. This machining facility is a machining facility notprovided with a setup station, in which workpieces may be mounted anddismounted on and from the sub-pallets at the sub-pallet stocker orworkpieces may be mounted and dismounted on and from the sub-pallets atother work tables.

Further, according to the present: invention, there is provided amachining facility having a sub-pallet for a workpiece to be mountedthereon and conveying the sub-pallet between units provided withsub-pallet carrying parts, which includes: at least one machine toolincluding a base supporting machine components, a spindle having a toolmounted thereon, a spindle head rotatably supporting the spindle, a mainpallet provided with a sub-pallet carrying part for carrying thereon asub-pallet for a workpiece to be mounted thereon, a pallet changer forchanging main pallets between a machining area and a machiningpreparation area, a driving means for relatively moving the spindle headalong X-, Y-, and Z-axes with respect to the main pallet, and adetecting means for detecting positions or movement amounts of feed axesoperated by the driving means; a plurality of sub-pallets for workpiecesto be mounted thereon, formed to be able to be mounted on a sub-palletcarrying part provided on the main pallet or a table of the machinetool; a setup station for mounting and dismounting a workpiece on andfrom the sub-pallet, the setup station having a sub-pallet carrying partfor carrying the sub-pallet thereon; a sub-pallet stocker including asub-pallet carrying table having a sub-pallet carrying part for carryingthe sub-pallet thereon, a positioning means provided on the sub-palletcarrying table and engaging with and positioning the sub-pallet, and anoil pan for receiving dropped chips and coolant solution; and asub-pallet conveyor system for conveying the sub-pallet between theunits, the sub-pallet conveyor system configured to include thesub-pallet carrying parts of the machine tool, the setup station and thesub-pallet stocker in a workable area thereof, wherein the sub-pallet isused to convey and machine a workpiece. The machine tool constitutingone unit of this machining facility is a machining center type in whichthe tool is mounted on the rotating spindle and is moved relative to themain pallet along the X-, Y-, and Z-axes. This machine tool has thepallet changer for changing the main pallet between the machining areaand the machining preparation area. Further, in the sub-pallet stocker,positioning means is used to position the sub-pallet on the sub-palletcarrying table and the dropped chips and coolant solution are receivedand collected by the oil pan.

Further, according to the present invention, there is provided amachining facility in which the sub-pallet conveyor system is amulti-articulated conveyor system having at least five swiveling axes.Since the conveyor system is the multi-articulated conveyor system, itis possible to convey the sub-pallet to any position in the workablearea of the sub-pallet conveyor system, and further change theorientation of the sub-pallet or slant the workpiece mounting surface ofthe sub-pallet.

Further, according to the present invention, there is provided amachining facility in which the setup station has a sub-pallet carryingpart for carrying the sub-pallet thereon with a workpiece mountingsurface facing upward and in which the machine tool has a sub-palletcarrying part for carrying the sub-pallet thereon with the workpiecemounting surface of the sub-pallet facing sideways. The setup work canbe performed at this setup station with the workpiece mounting surfaceof the sub-pallet facing upward, while the sub-pallet can be conveyedafter the orientation thereof is changed so that the workpiece mountingsurface of the sub-pallets are turned sideways for machining with gooddischarge of the chips at the machine tool.

Further, according to the present invention, there is provided amachining facility in which the unit provided with the sub-palletcarrying part has a reference mark of known relative positioncoordinates with respect to the sub-pallet carrying part of the unit andin which the sub-pallet conveyor system has an image recognizing meansfor recognizing an image of the reference mark, so that the recognizedimage of the reference mark and a position information of the sub-palletconveyor system is used to position a gripper of the sub-pallet conveyorsystem and the sub-pallet carrying part of the unit. In this machiningfacility, the cross or other reference mark, is made the unit havingsub-pallet carrying part, such as the machine tool, setup station andsub-pallet stocker, and is recognized by image recognizing meansprovided en the sub-pallet conveyor system to read the position,information of the sub-pallet conveyor system at that time. Since therelative position coordinates of the reference mark and the sub-palletcarrying part of the unit are known, it is possible to automaticallyposition the gripper of the sub-pallet conveyor system and thesub-pallet carrying part of the unit relative to each other whenrecognizing the image of a reference mark.

Further, according to the present invention, there is provided amachining facility in which the sub-pallet conveyor system has a weightmeasuring means for measuring a weight of a gripped article or a shapemeasuring means for measuring a shape of a gripped article, so that theresult of measurement of the weight or shape is compared withpredetermined numerical values to judge that mistaken mounting of theworkpiece has been made. In this machining facility, the measured weightvalue or dimension value is compared with the predetermined weightreference value or dimension reference value and, when exceeding thepredetermined value, it is judged that the mistaken mounting of theworkpiece has been made.

Further, according to the present invention, there is provided amachining facility which further includes a cleaning tool for removingchips and coolant solution attached on the sub-pallet and the workpiece,the cleaning tool having a gripped part gripped by a gripper of thesub-pallet conveyor system. The sub-pallet conveyor system of thismachining facility grips a cleaning tool instead of the sub-pallet bythe gripper, moves the cleaning tool near the sub-pallet mounted on thesub-pallet carrying part of each unit, and removes the chips and coolantsolution attached on the sub-pallet and the workpiece by blowing air,suction, brushing, etc.

Further, according to the present invention, there is provided amachining facility having a sub-pallet for a workpiece to be mountedthereon and conveying the sub-pallet between units provided withsub-pallet carrying parts, which includes: at least one machine toolhaving a pallet changer for changing main pallets; a plurality ofsub-pallets for a workpiece to be mounted thereon, formed to be able tobe mounted on a sub-pallet carrying part provided on the main pallet; asetup station for mounting and dismounting a workpiece on and from thesub-pallet, the setup station having a sub-pallet carrying part forcarrying the sub-pallet thereon; a sub-pallet stocker having asub-pallet carrying part for carrying the sub-pallet thereon; a cleaningstation for removing chips and coolant solution attached on thesub-pallet and the workpiece, the cleaning station having a sub-palletcarrying part for carrying the sub-pallet thereon and including asub-pallet swiveling mechanism for making the sub-pallet turn; and asub-pallet conveyor system for conveying the sub-pallet and driving theswiveling mechanism of the cleaning station, the sub-pallet conveyorsystem having a hand for gripping the sub-pallet and configured toinclude the sub-pallet carrying parts of the machine tool, the setupstation, the sub-pallet stocker and the cleaning station in a workablearea thereof, wherein the sub-pallet is used to convey and machine aworkpiece. At the cleaning station of this machining facility, asub-pallet having the machined sub-pallet mounted thereon is mounted onthe sub-pallet mounting part and then the attached chips and coolantsolution is removed by spraying a cleaning coolant solution, blowingair, suction, brushing, etc. while turning the sub-pallet.

Further, according to the present invention, there is provided amachining facility having a sub-pallet for a workpiece to be mountedthereon and conveying the sub-pallet between, units provided withsub-pallet carrying parts, which includes: at least one machine toolincluding a base supporting machine components, a spindle having a tool,mounted thereon, a spindle head rotatably supporting the spindle, a mainpallet or table provided with a sub-pallet carrying part for carryingthereon a sub-pallet for a workpiece to be mounted thereon, a drivingmeans for relatively moving the spindle head along X-, Y-, and Z-axeswith respect to the main pallet or the table, and a detecting means fordetecting positions or movement amounts of feed axes operated by thedriving means, a plurality of sub-pallets for a workpiece to be mountedthereon, formed to be able to be mounted on a sub-pallet carrying partprovided on the main pallet or the table of the machine tool; a setupstation for mounting and dismounting a workpiece on and from thesub-pallet, the setup station having a sub-pallet carrying part forcarrying the sub-pallet thereon; a sub-pallet stocker including asub-pallet carrying table having a sub-pallet carrying part for carryingthe sub-pallet thereon, a positioning means provided on the sub-palletcarrying table and engaging with and positioning the sub-pallet, and anoil pan for receiving dropped chips and coolant; and a multi-articulatedsub-pallet conveyor system for conveying the sub-pallet between theunits, the sub-pallet conveyor system having at least five swivelingaxes and configured to include the sub-pallet carrying parts of themachine tool, the setup station and the sub-pallet stocker in a workablearea thereof, wherein the sub-pallet is used to convey and machine aworkpiece. The machine tool of this machining facility can mount thesub-pallet conveyed by the sub-pallet conveyor system and machine iteven without including the main pallet changer if having the sub-palletcarrying part on the table or the angle plate or rotary table providedon the table.

Further, according to the present invention, there is provided a machinetool machining a workpiece by moving a tool and the workpiece mounted ona sub-pallet relative to each other, which includes: a pallet changerfor changing main pallets; a pallet mounting table moving relatively toa spindle head having the tool mounted thereon along X-, Y-, and Z-axesand having a shaft for making the main pallet turn; and a sub-palletmounting means for mounting the sub-pallet for a workpiece to be mountedthereon on a sub-pallet carrying part provided on the main pallet,wherein a workpiece conveyed using the main pallet and the sub-pallet ismachined. In this machine tool, the sub-pallet having the workpiecemounted thereon is mounted on the sub-pallet carrying part provided onthe main pallet and the workpiece conveyed using the main pallet and thesub-pallet is machined.

Further, according to the present invention, there is provided a machinetool machining a workpiece by moving a tool and the workpiece mounted ona sub-pallet relative to each other, which includes: a pallet changerfor changing main pallets; a pallet mounting table moving relatively toa spindle head having the tool mounted thereon along X-, Y-, and Z-axesand having a shaft for making the main pallet turn; a rotary table forthe sub-pallet to be mounted thereon, the rotary table provided on themain pallet; and a sub-pallet mounting means for mounting the sub-palletfor a workpiece to be mounted thereon on the rotary table, thesub-pallet mounting means provided on the rotary table, wherein, aworkpiece conveyed using the main pallet and the sub-pallet is machined.This machine tool further includes the rotary table on the rotatablemain pallet and, by mounting the sub-pallet having the workpiece mountedthereon on the sub-pallet carrying part of the rotary table, can machinethe workpiece using five axes, that is, three axes of linear motion andtwo axes of rotation.

Further, according to the present invention, there is provided a setupstation for carrying a sub-pallet thereon and mounting and dismounting aworkpiece on and from the sub-pallets, which includes: a sub-palletcarrying table having a sub-pallet carrying part for carrying thesub-pallet thereon with a workpiece mounting surface of the sub-palletfacing upward; a positioning means provided on the sub-pallet carryingtable and engaging with and positioning the sub-pallet; and an indexingmeans for turning and indexing the sub-pallet carrying table. Thesub-pallet carried on this setup station is positioned on the sub-palletcarrying table and suitably rotationally indexed by the indexing means,and the setup work including the mounting and dismounting of theworkpiece is performed on the indexed sub-pallet.

Further, according to the present invention, there is provided asub-pallet stocker for carrying thereon a sub-pallet having a workpieceto be mounted thereon, which includes: a sub-pallet carrying tablehaving a sub-pallet carrying part for carrying the sub-pallet thereon; apositioning means provided on the sub-pallet carrying table and engagingwith and positioning the sub-pallet; and a reference mark provided at apredetermined position of the sub-pallet stocker and having knownrelative position coordinates with respect to the sub-pallet carryingpart. Since this sub-pallet stocker is provided with the reference markof known relative position, coordinates with respect to the sub-palletcarrying part, when used in a machining facility, it is possible torecognize the image of the reference mark by the image recognizing meansprovided in the sub-pallet conveyor system and automatically positionthe gripper of the sub-pallet conveyor system and the sub-palletcarrying part.

Further, according to the present invention, there is provided asub-pallet stocker for carrying thereon a sub-pallet having a workpieceto be mounted thereon, which includes: a sub-pallet carrying cablehaving a sub-pallet carrying part for carrying thereon the sub-pallet ata slant so that chips and coolant solution will drop off; a positioningmeans provided on the sub-pallet carrying table and engaging with andpositioning the sub-pallet; and an oil pan for receiving the droppedchips and coolant solution. Since this sub-pallet stocker carries andpositions the sub-pallet at a slant, the chips and coolant solutionattached on the sub-pallet and workpiece carried after machining easilydrop into the oil pan.

Further, according to the present invention, there is provided asub-pallet for a workpiece to be mounted thereon, mounted on a machinetool, which includes: a workpiece mounting surface for a workpiece to bemounted thereon; a mounted part formed to be able to be mounted on asub-pallet carrying part provided on a main pallet changed by a palletchanger of the machine tool; and a gripped part for being gripped by asub-pallet conveyor system when conveying the sub-pallet, wherein thesub-pallet is used to mount and convey a workpiece. This sub-pallet, onwhich the workpiece is mounted, can be gripped by the sub-palletconveyor system, and is mounted on the sub-pallet carrying part providedon the main pallet.

Further, according to the present invention, there is provided asub-pallet for a workpiece to be mounted thereon, mounted on a machinetool, which includes: a workpiece mounting surface for a workpiece to bemounted thereon; a mounted part formed to be able to be mounted on asub-pallet carrying part provided on a main pallet changed by a palletchanger of the machine tool; a gripped part for being gripped by asub-pallet conveyor system when conveying the sub-pallet; and a suctionhole communicated with an air suction pipe extending to a main pallet ofthe machine tool and opening to the workpiece mounting surface so thatthe mounted surface of the workpiece mounted using a workpiece mountingmeans is sucked to the workpiece mounting surface, wherein thesub-pallet is used, to mount and convey a workpiece. When thissub-pallet is mounted on the main pallet of the machine tool, themounted surface of the mounted workpiece is sucked through the suctionpipe and suction hole and made to closely contact with the workpiecemounting surface of the sub-pallet.

Further, according to the present invention, there is provided asub-pallet for a workpiece to be mounted thereon, mounted on a machinetool, which includes: a workpiece mounting surface for a workpiece to bemounted thereon; a mounted means formed to be able to be mounted on asub-pallet carrying part provided on a main pallet changed by a palletchanger of the machine tool; and a handle attached to the sub-pallet ina state projecting from a side surface, wherein the sub-pallet is usedto mount and convey a workpiece. In a machining facility which does notinclude a sub-pallet conveyor system or in a machining facility in whicha sub-pallet conveyor system breaks down, the operator can grip thehandle of the sub-pallet to convey the sub-pallet among the machinetool, setup station, sub-pallet stocker, and other units.

According to the present invention, a common sub-pallet carrying part onwhich a sub-pallet can be carried, is provided on a machining tool,setup station, sub-pallet stocker, cleaning station, etc., to form aunit, and a desired machining facility can be quickly constructed byincreasing or decreasing the units in accordance with the requiredspecifications of the machining facility, and quickly construct amachining facility. If using as the sub-pallet conveyor system amulti-articulated conveyor system having at least five swiveling axes,it is possible to move a sub-pallet to any position in a work area ofthe conveyor system and possible to change the orientation of theworkpiece mounting surface of the sub-pallet, slant it, or otherwisegive diverse motion. In this way, by forming units, using sub-pallets,etc., it is possible to construct a machining facility using asub-pallet with flexibility.

Further, since the sub-pallet stocker is designed to store thesub-pallet at a slant, the chips or coolant solution attached on thesub-pallet and workpiece easily drop off. Further, it becomes possibleto automatically removing the chips or coolant solution attached on thesub-pallet and workpiece by using the sub-pallet conveyor system to gripthe cleaning tool and perform the cleaning operation or providing thecleaning station with the sub-pallet swiveling mechanism able to bedriven by the sub-pallet conveyor system.

Further, since the workpieces are changed by mounting the workpieces onthe sub-pallets and conveying the sub-pallets among the machine tool,setup station and other units, it is possible to quickly convey theworkpieces and reduce the size of the conveyor system compared with thecase where the workpieces are changed by conveying main pallets.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a first embodiment of a machining facilityaccording to the present invention, which includes one machine tool.

FIG. 2 is a plan view showing a second embodiment of a machiningfacility according to the present invention, which includes two machinetools and a self-propelled sub-pallet conveyor system.

FIG. 3 is a cross-sectional view showing the configuration of a setupstation.

FIG. 4 is a perspective view showing the configuration of a sub-palletconveyor system.

FIG. 5 is an explanatory view illustrating the state where a handattached to the front end of an arm of the sub-pallet, conveyor systemgrips a sub-pallet.

FIG. 6 is a bottom view, as viewed along the arrow D, of the hand andsub-pallet shown in FIG. 5.

FIG. 7 is a side view showing the configuration of a sub-pallet stocker.

FIG. 8 is a front view showing the configuration of the sub-palletstocker.

FIG. 9 is an enlarged cross-sectional view of a part E-E of FIG. 8.

FIG. 10 is a cross-sectional view of the part F-F of FIG. 9.

FIG. 11 is an explanatory view showing a configuration wherein a hand ofa sub-pallet conveyor system is provided with an image recognizingmeans, weight measuring means, and shape measuring means.

FIG. 12 is an explanatory view illustrating the case wherein the hand ofthe sub-pallet conveyor system is used to grip a cleaning tool.

FIG. 13 is an explanatory view illustrating a configuration wherein ahand of a sub-pallet conveyor system is used to drive a sub-palletswiveling mechanism of a cleaning station.

FIG. 14 is a cross-sectional view showing a configuration of asub-pallet having a suction hole and handles.

FIG. 15 is a front view of the sub-pallet shown in FIG. 14.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be described belowwith reference to the accompanying drawings.

In FIG. 1, the machining facility of the first embodiment is comprisedof a machine tool 1 constituted by a horizontal machining center, onesetup station 5 where a workpiece is mounted and dismounted on and froma sub-pallet 3, five sub-pallet stockers 7 for sub-pallets 3 to beplaced thereon, and a sub-pallet conveyor system 9 conveying sub-pallet3 among units, i.e., machine tool 1, setup station 5, and sub-palletstockers 7.

Machine tool 1 is a horizontal machining center and includes a column 33moving on a bed 31 constituting a base in the direction along an X-axis,i.e., the left-right direction, a spindle head 35 moving on column 33 inthe direction along a Z-axis, i.e., the up-down direction (directionvertical to paper surface), a spindle 37 supported rotatably by spindlehead 35 and mounting a tool at the front end thereof, a pallet mountingtable 41 moving on bed 31 in the direction along the Z-axis, i.e., thefront-back direction, and detachably mounting a main pallet 39, and apallet changer 47 gripping main pallets 39 and making them turnsimultaneously like in arrow 23 for change between a machiningpreparation area 43 where main pallet 39 is kept on standby and amachining area 45 in which pallet mounting table 41 is provided. Palletmounting table 41 has a rotation shaft rotating in the direction along aB-axis and can make main pallet 39 rotate in the horizontal plane. Mainpallet 39 has a rotary table body 21 provided thereon, and rotary tablebody 21 has attached thereto a rotary table 49 having a rotation shaftrotating in the direction along a C-axis. A sub-pallet 3 is detachablymounted on the vertical surface of rotary table 49. The detailedstructure of a sub-pallet carrying part for mounting sub-pallet 3 onrotary table 49 will be described later. While not shown, the X-, Y-,and Z-feed axes are provided with driving means, and the positions oramounts of movement along the feed axes are detected by detecting meansfor positional control. Main pallet 39 may include, instead of rotarytable body 21, an angle plate provided thereon, on which sub-pallet 3 ismounted. The sub-pallet may also be directly mounted on main pallet 39without any angle plate.

At setup station 5, the workpiece is mounted on sub-pallet 3, and thensub-pallet 3 is gripped by a hand 95 of sub-pallet conveyor system 9 andmounted to rotary table 49 on main pallet 39 in the machiningpreparation area 43 of machine tool 1. Sub-pallet 3 in the machiningpreparation area 43 is moved by pallet changer 47 to pallet mountingtable 41 in machining area 45, where workpiece W mounted on sub-pallet 3is machined. Sub-pallet 3 having machined workpiece W mounted thereon ismoved by pallet changer 47 from machining area 45 to machiningpreparation area 43 and is conveyed by sub-pallet conveyor system 9 tosetup station 5. At setup station 5, machined workpiece W is dismountedfrom sub-pallet 3. Sub-pallet conveyor system 9 also conveys sub-pallet3 between setup station 5 and sub-pallet stockers 7 and between machinetool 1 and sub-pallet stockers 7. This machining facility is controlledby a not shown computer.

In FIG. 2, the machining facility of the second embodiment is comprisedof two machine tools, a machining tool 11 constituted by a horizontalmachining center and a machine tool 13 constituted a vertical machiningcenter, two setup stations 15 where workpieces are mounted anddismounted on and from sub-pallets 3, three sub-pallet stockers 19 eachof which allows three sub-pallets 3 to be carried thereon, one cleaningstation 25 into which sub-pallet 3 is put to remove attached chips andcoolant solution, and a self-propelled sub-pallet conveyor system 27conveying sub-pallet 3 among the units, i.e., machine tools 11 and 13,setup stations 15, sub-pallet stockers 19, and cleaning station 25.

Machine tool 11 has the same configuration as that of horizontalmachining center 1 of FIG. 1, and therefore the explanation will beomitted. Machine tool 13 is a vertical machining center which includes acolumn 53 moving on a bed 51 constituting a base in the direction alonga Y-axis, i.e., the front-rear direction, a spindle head 55 moving oncolumn 53 in the direction along a Z-axis, i.e., the up-down direction(direction vertical to paper surface), a spindle 57 supported rotatablyby spindle head 55 and mounting a tool on the bottom end thereof, and atable 59 moving on bed 51 in the direction along an X-axis, i.e., theleft-right direction. Table 59 has a rotary table body 17 providedthereon, which in turn has a rotary table 61 rotating in the direction,along an A-axis. A sub-pallet 3 is detachable/mounted on the verticalsurface of rotary table 61. The detailed structure of a sub-palletcarrying part mounting sub-pallet 3 on rotary table 61 will be describedlater.

In the machining facility of the second embodiment, sub-pallet conveyorsystem 27 can be self propelled and convey sub-pallet 3 between unitsinstalled in a broad area. Further, it is possible to perform a firstprocess of machining on a workpiece W by machine tool 11 and then conveya sub-pallet 3 no machine tool 13, where a second process of machiningis performed on the same workpiece W. After the machining, sub-pallet 3can be conveyed to cleaning station 25 where chips and coolant solutionattached to sub-pallet 3 or workpiece W are removed. In accordance withthe number or type of workpieces W to be machined, it is also possibleto increase the types or numbers of the machine tools and possible toform sub-pallet stockers 19 in multi-levels.

In setup station 5, 15 of FIG. 3, a sub-pallet carrying table 65 isrotatably supported on the top of a base 63. Sub-pallet placing table 65has a generally-angular U-shaped cross-section. Columnar positioningpins 67 limiting the position of sub-pallet 3 in the gravity directionare implanted at the four corners of the top surface, while conicalpositional pins 69 limiting the position of sub-pallet 3 in thehorizontal direction are implanted at two diagonal corners. On thebottom surface of sub-pallet 3, conical holes 71 are formed at positionscorresponding to positioning pins 69. When sub-pallet 3 is carried onsub-pallet carrying table 65, four positioning pins 67 support thebottom surface of sub-pallet 3 and two positioning pins 69 engage withholes 71 to thereby arrange sub-pallet 3 at a predetermined positionwith workpiece mounting surface 73 facing upward. Base 63 is providedwith an indexing pin 79 to be inserted from the horizontal directioninto any one of four indexing holes 77 formed, equidistantly at fourlocations on the circumference or a shaft part 75 projecting downwardfrom sub-pallet carrying table 65. This indexing pin 79 is linked with apedal 81 provided at the lower part of base 63. When an operatordepresses pedal 81, indexing pin 79 is disengaged from indexing hole 77,sub-pallet carrying table 65 can be turned by hand, and the orientationof horizontal turning of sub-pallet 3 can be changed by 90 degreeintervals, thereby facilitating the mounting work of workpiece W.Instead of horizontal turning, it is also possible to employ aconfiguration in which workpiece mounting surface 73 of sub-pallet 3 canbe turned to slant to the operator side. For the method of mountingworkpiece W to workpiece mounting surface 73, the method of inserting ahand from the cavity of sub-pallet carrying table 65 to insert a bolt ina through hole formed in sub-pallet 3 from the bottom side and screwingit into a tap hole formed at the bottom surface of workpiece W to fastenit is used. This method can be easily performed because sub-pallet 3 isthinner than main pallet 39 as shown in the figure. Of course, themethod of using a fastener to mount workpiece W to workpiece mountingsurface 73 from the side of workpiece mounting surface 73 by an ordinarymethod can be also employed, but sometimes the fastener and tool end upinterfering.

FIG. 4 shows, as a sub-pallet conveyor system, an embodiment of amulti-articulated conveyor system having at least five swiveling axes.In this embodiment, sub-pallet conveyor system 9, 27 has six swivelingaxes J1 to J6, and a first arm 85, a second arm 87, a third arm 89, afourth arm 91, and a front end 93 can turn on base 83. The “at leastfive swiveling axes” refer to J1 to J5. If providing a self propellingmeans under base 83, sub-pallet conveyor system 9, 27 can move on rails29 laid on the floor surface as shown in FIG. 2 and the workable area isenlarged. Sub-pallet conveyor system 9, 27 is instructed to operate byteaching or programming and is controlled to be driven by a controlsystem.

In FIG. 5, hand 95 serving as a gripping means attached to front end 93of sub-pallet conveyor system 9, 27 of FIG. 4 is provided with a pair ofair cylinders 99 at the two ends of a base plate 97 attached to frontend 93. Base plate 97 is provided with rails 101, so that a pair offingers 105 can be moved linearly by sliders 103 so as to become closeror farther in distance. Fingers 105 are coupled to pistons 107 of aircylinders 99, and air cylinders 99 are controlled so that the pair offingers 105 can synchronously make grippers 109 engage with anddisengage from gripped parts 111 of sub-pallet 3. As shown in FIG. 6,two grippers 109 are provided at each finger 105 so as to project outfrom finger 105, while two gripped parts 111 are formed at each of twoside surfaces of sub-pallet 3. The surroundings of base plate 97 are;covered by a cover 113.

Sub-pallet stockers 7, 19 carry sub-pallets 3 with workpiece mountingsurfaces 73 of sub-pallets 3 facing upward. As opposed to this, FIGS. 7and 8 show a sub-pallet stocker 121 carrying sub-pallets 3 slanted inthree levels and two columns so as to reduce the installation area. Aframe 123 is provided with a total of six sub-pallet carrying tables 125carrying sub-pallets 3 slanted in three levels, a top, middle, andbottom level and in two columns, a left and right column. Sub-pallets 3are carried slanted down to the right slightly from the front view so asto help the attached coolant solution collect into one location and dropdown. Below each sub-pallet carrying table 125, an oil pan 139 isprovided so that it receives the chips and coolant solution droppingdown from sub-pallet 3 and workpiece W. As shown in FIG. 7, ifsub-pallet carrying tables 125 are provided slanted down to the rightslightly, the coolant solution, received by oil pans 139 at the sixlocations will not remain still, but will be easily guided to thebottommost location and therefore can be easily collected.

On the top bottom surface of sub-pallet 3 carried on sub-pallet stocker121, two pins 127 are provided so as to project out and spaced apart inthe left-right directions. As shown in FIGS. 9 and 10, the front ends ofpins 127 have large diameter parts 129. Each sub-pallet carrying table125 is formed with elongated holes 131 at two locations corresponding topins 127. Positioning plates 133 are fixed to sub-pallet carrying table125 so as to cover the bottom, parts of elongated holes 131. Elongatedholes 131 are sized to be somewhat larger than large diameter parts 129of pins 127. Positioning plates 133 are formed with semicircular notchgrooves 135 sized to be somewhat larger than the diameters of pins 127.An abutting plate 137 abutting against the center of the lower part ofthe bottom surface of sub-pallet 3 is fixed to sub-pallet carrying table125. Pins 127 of Sub-pallet 3 gripped by hand 95 of sub-pallet conveyorsystem 9, 27 is inserted into elongated holes 131 in a posturesubstantially parallel to the slanted surface of sub-pallet carryingtable 125 and then the pallet 3 is lowered until pins 127 engage withnotch grooves 135. When the grip of hand 95 is released, sub-pallet 3 iscarried on sub-pallet carrying table 125 using gravity so as not to falloff.

Further, a reference mark 141 is made at the top left of the frame ofsub-pallet stocker 121, and relative position coordinates a1, a2, b1,b2, and b3 between the reference mark and center points 143 ofsub-pallet carrying tables 125 are stored in advance in the controlsystem for sub-pallet conveyor system 9, 27. Hand 95 of sub-palletconveyor system 9, 27 is provided with a camera 145 as an imagerecognizing means (see FIG. 11), which recognizes the reference mark.Using the position information of sub-pallet conveyor system 9, 27detected by position detectors or the like provided at the swivelingaxes and propelling means of sub-pallet conveyor system 9, 27 whenrecognizing the reference mark and the stored positional, coordinatesbetween the reference mark and center points 143 of sub-pallet carryingtables 125, grippers 109 of fingers 105 of sub-pallet conveyor system 9,27 and gripped parts 111 of sub-pallet 3 carried on sub-pallet carryingtable 125 of sub-pallet stocker 121 are automatically and quicklypositioned. Due to this, the work of teaching the carrying positions ofall sub-pallets 3 to sub-pallet conveyor system 9, 27 becomesunnecessary.

Reference marks 141 are preferably provided near the sub-pallet carryingparts of various units, i.e., the machine tool, setup station, andcleaning station, so that grippers 109 of fingers 105 of sub-palletconveyor system 9, 27 and gripped parts 111 of sub-pallet 3 carried oneach unit are positioned with respect to each other similarly.

In FIG. 11, by providing a load sensor or other weight measuring means147 between front end 93 of sub-pallet conveyor system 9, 27 and hand95, it is possible to measure the weight of workpiece W mounted onsub-pallet 3. The measurement value of the weight is compared with apredetermined weight value of workpiece W. When exceeding the acceptablerange, the control system judges that mistaken mounting of the workpiecehas been made and, for example, issues an alarm. Further, by providingbase plate 97 of hand 95 with a contact-type shape measuring means 149or non-contact type shape measuring means 151 faced toward workpiecemounting surface 73 of sub-pallet 3 to be gripped, it is possible tomeasure the shape and dimensions of workpiece W mounted on sub-pallet 3.The measurement values of the shape and dimensions are compared with thepredetermined values of the shape and dimensions of workpiece W. Whenexceeding the acceptable range, the control system judges that mistakenmounting of the workpiece has been made and, for example, issues analarm.

In FIG. 12, hand 95 of sub-pallet conveyor system 9, 27 can grip,instead of sub-pallet 3, a cleaning tool 153 carried on a specificsub-pallet carrying table 125 of sub-pallet stocker 121. For thisreason, cleaning tool 153 has gripped parts of dimensions substantiallythe same as sub-pallet 3 and has a suction port 155 and a suction pipe157. The outlet of suction pipe 157 is connected to a separate suctionsystem 159 by a flexible hose 161. Sub-pallet conveyor system 9, 27appropriately grips cleaning tool 153 instead of sub-pallet 3 to bringits suction port 155 close to sub-pallet 3 and workpiece W placed oneach of the units, i.e., the machine tool, setup station, and sub-palletstocker, and removes the attached chips and coolant solution. If usingan air blow system instead of suction system 159, the chips and thecoolant solution can be blown off. Further, it is also possible toprovide cleaning tool 153 with brush and use multi-articulatedsub-pallet conveyor system 9, 27 to give the brush movement to removethe chips.

In FIG. 13, cleaning station 25 has a sub-pallet swiveling mechanismmaking the sub-pallet 3 mounted in the hermetically closed cover swivelback and forth as shown by an arrow 175. Sub-pallet swiveling mechanismis comprised of a rotary table 163 for sub-pallet 3 to be mountedthereon, rotatably supported on the frame of cleaning station 25, threesprockets 165 and a chain 167 for making rotary table 163 turn, and arod 169 attached to the middle of chain 167 and extending through theupper cover. The top part of rod 169 has a conical projection 173engaging with a hole 171 of finger 105 of sub-pallet conveyor system 9,27. By moving hand 95 of sub-pallet conveyor system 9, 27 up and down,as shown by an arrow 177, with projection 173 inserted in hole 171,rotary table 163 swivels back and forth and, if necessary, a washingsolution is sprayed in a shower state or air is blown, to remove thechips or coolant, solution attached on sub-pallet 3 and workpiece W.Further, the door of cleaning station 25 may also be opened and closedusing the motion of sub-pallet conveyor system 9, 27.

In FIG. 14, rotary table 49 mounted on main pallet 39 is provided withan air suction pipe 181, and an abutting piece 187 is biased by a spring185 so as to project out a little from mounting surface 183 ofsub-pallet 3. By engagement of male side positioning clamp pinsprojecting from the bottom surface of sub-pallet 3 with female sidepositioning clamps 191 provided at two corresponding locations of rotarytable 49, sub-pallet 3 is positioned and mounted on rotary table 49. Formale side positioning clamp pins 189 and female side positioning clamps191, it is possible to use a well-known combination of engagement oftaper cones and taper holes as well as pull studs and collet chucks usedbetween main pallet 39 and pallet mounting table 41 and also possible touse commercially available well-known positioning clamps. A suction hole193 extends through sub-pallet 3 at a position corresponding to abuttingpiece 187, while a suction hole 193 communicates with suction pipe 181.A workpiece WA having a recessed cross-sectional shape is mounted tosub-pallet 3 by the method of using four bolts to pull sub-pallet 3 infrom the bottom of sub-pallet 3. By sucking mounted surface 195 ofworkpiece W through suction hole 193, even during machining, it ispossible to make mounted surface 195 of workpiece W closely contact withworkpiece mounting surface 73 of sub-pallet 3.

In FIGS. 14 and 15, the two side surfaces of sub-pallet 3 are providedwith handles 197 for being gripped by the operator, so that it ispossible for the operator to convey sub-pallet 3 between the unitswithout using sub-pallet conveyor system 9, 27. This is useful in thecase of a machining facility not provided with sub-pallet conveyorsystem 9, 27 and, further, is effective in the case where sub-palletconveyor system 9, 27 breaks down.

Further, both when mounting sub-pallet 3 to rotary table 61 on table 59of machine tool 13 of the vertical machining center and when mountingsub-pallet 3 on rotary table 163 of cleaning station 25, a combinationof male side positioning clamp pins 189 and female side positioningclamps 191 is used. Rotary tables 49 and 61 may be NC rotary tables orindex tables. Further, the machine tool, one of the units, may be an NCmilling machine, lathe, grinding machine, electrodischarge machine, orother type of machine tool.

1. A machining facility having a sub-pallet for a workpiece to bemounted thereon and conveying the sub-pallet between units provided withsub-pallet carrying parts, said machining facility comprising: at leastone machine tool having a pallet changer for changing main pallets; aplurality of sub-pallets for a workpiece to be mounted thereon, formedto be able to be mounted on a sub-pallet carrying part provided on saidmain pallet; a setup station for mounting and dismounting a workpiece onand from said sub-pallet, said setup station having a sub-palletcarrying part for carrying said sub-pallet thereon; a sub-pallet stockerhaving a sub-pallet carrying part for carrying said sub-pallet thereonand configured to stock said sub-pallet at a slant so that chips andcoolant solution will drop off when said sub-pallet is carried on saidsub-pallet stocker; and a sub-pallet conveyor system for conveying saidsub-pallet, said sub-pallet conveyor system having a hand for grippingsaid sub-pallet and configured to include said sub-pallet carrying partsof said machine tool, said setup station and said sub-pallet stocker ina workable area thereof, wherein said sub-pallet is used to convey andmachine a workpiece.
 2. The machining facility according to claim 1,wherein said sub-pallet conveyor system comprises a multi-articulatedconveyor system having at least five swiveling axes.
 3. The machiningfacility according to claim 1, wherein said setup station has asub-pallet carrying part for carrying said sub-pallet thereon with aworkpiece mounting surface of said sub-pallet facing upward, and whereinsaid machine tool has a sub-pallet carrying part for carrying saidsub-pallet thereon with the workpiece mounting surface of saidsub-pallet facing sideways.
 4. The machining facility according to claim1, wherein said unit provided with said sub-pallet carrying part has areference mark of known relative position coordinates with respect tosaid sub-pallet carrying part of said unit, and said sub-pallet conveyorsystem has an image recognizing means for recognizing an image of saidreference mark, so that the recognized image of the reference mark and aposition information of said sub-pallet conveyor system is used toposition a gripper of said sub-pallet conveyor system and saidsub-pallet carrying part of said unit.
 5. The machining facilityaccording to claim 1, wherein said sub-pallet conveyor system has aweight measuring means for measuring a weight of a gripped article or ashape measuring means for measuring a shape of a gripped article, sothat the result of measurement of the weight or shape is compared withpredetermined numerical values to judge that mistaken mounting of theworkpiece has been made.
 6. The machining facility according to claim 1,further comprising a cleaning tool for removing chips and coolantsolution attached on said sub-pallet and said workpiece, said cleaningtool having a gripped part gripped by a gripper of said sub-palletconveyor system.
 7. A machining facility having a sub-pallet for aworkpiece to be mounted thereon and conveying the sub-pallet betweenunits provided with sub-pallet carrying parts, said machining facilitycomprising: at least one machine tool having a pallet changer forchanging main pallets; a plurality of sub-pallets for a workpiece to bemounted thereon, formed to be able to be mounted on a sub-palletcarrying part provided on said main pallet; a sub-pallet stocker havinga sub-pallet carrying part for carrying said sub-pallet thereon andconfigured to stock said sub-pallet at a slant so that chips and coolantsolution will drop off when said sub-pallet is carried on saidsub-pallet stocker; and a sub-pallet conveyor system for conveying saidsub-pallet, said sub-pallet conveyor system having a hand for grippingsaid sub-pallet and configured to include said sub-pallet carrying partsof said machine tool and said sub-pallet stocker in a workable areathereof, wherein said sub-pallet is used to convey and machine aworkpiece.
 8. A machining facility having a sub-pallet for a workpieceto be mounted thereon and conveying the sub-pallet between unitsprovided with sub-pallet carrying parts, said machining facilitycomprising: at least one machine tool including a base supportingmachine components, a spindle having a tool mounted thereon, a spindlehead rotatably supporting said spindle, a main pallet provided with asub-pallet carrying part for carrying thereon a sub-pallet for aworkpiece to be mounted thereon, a pallet changer for changing mainpallets between a machining area and a machining preparation area, adriving means for relatively moving said spindle head along X-, Y-, andZ-axes with respect to said main pallet, and a detecting means fordetecting positions or movement amounts of feed axes operated by saiddriving means; a plurality of sub-pallets for a workpiece to be mountedthereon, formed to be able to be carried on a sub-pallet carrying partprovided on said main pallet or a table of said machine tool; a setupstation for mounting and dismounting a workpiece on and from saidsub-pallet, said setup station having a sub-pallet carrying part forcarrying said sub-pallet thereon; a sub-pallet stocker including asub-pallet carrying table having a sub-pallet carrying part for carryingsaid sub-pallet thereon, a positioning means provided on said sub-palletcarrying table and engaging with and positioning said sub-pallet, and anoil pan for receiving dropped chips and coolant solution; and asub-pallet conveyor system for conveying said sub-pallet between saidunits, said sub-pallet conveyor system configured to include saidsub-pallet carrying parts of said machine tool, said setup station andsaid sub-pallet stocker in a workable area thereof, wherein saidsub-pallet is used to convey and machine a workpiece.
 9. A machiningfacility having a sub-pallet for a workpiece to be mounted thereon andconveying the sub-pallet between units provided with sub-pallet carryingparts, said machining facility comprising: at least one machine toolhaving a pallet changer for changing main pallets; a plurality ofsub-pallets for a workpiece to be mounted thereon, formed to be able tobe mounted on a sub-pallet carrying part provided on said main pallet; asetup station for mounting and dismounting a workpiece on and from saidsub-pallet, said setup station having a sub-pallet carrying part forcarrying said sub-pallet thereon; a sub-pallet stocker having asub-pallet carrying part for carrying said sub-pallet thereon; acleaning station for removing chips and coolant solution attached onsaid sub-pallet and said workpiece, said cleaning station having asub-pallet carrying part for carrying said sub-pallet thereon andincluding a sub-pallet swiveling mechanism for making said sub-palletturn; and a sub-pallet conveyor system for conveying said sub-pallet anddriving said swiveling mechanism of said cleaning station, saidsub-pallet conveyor system having a hand for gripping said sub-palletand configured to include said sub-pallet carrying parts of said machinetool, said setup station, said sub-pallet stocker and said cleaningstation in a workable area thereof, wherein said sub-pallet is used toconvey and machine a workpiece.
 10. A machining facility having asub-pallet for a workpiece to be mounted thereon and conveying thesub-pallet between units provided with sub-pallet carrying parts, saidmachining facility comprising: at least one machine tool including abase supporting machine components, a spindle having a tool mountedthereon, a spindle head rotatably supporting said spindle, a main palletor table provided with a sub-pallet carrying part for carrying thereon asub-pallet for a workpiece to be mounted thereon, a driving means forrelatively moving said spindle head along X-, Y-, and Z-axes withrespect to said main pallet or said table, and a detecting means fordetecting positions or movement amounts of feed axes operated by saiddriving means; a plurality of sub-pallets for a workpiece to be mountedthereon, formed to be able to be carried on a sub-pallet carrying partprovided on said main pallet or said table of said machine tool; a setupstation for mounting and dismounting a workpiece on and from saidsub-pallet, said setup station having a sub-pallet carrying part forcarrying said sub-pallet thereon; a sub-pallet stocker including asub-pallet carrying table having a sub-pallet carrying part for carryingsaid sub-pallet thereon, a positioning means provided on said sub-palletcarrying table and engaging with and positioning said sub-pallet, and anoil pan for receiving dropped chips and coolant solution; and amulti-articulated sub-pallet conveyor system for conveying saidsub-pallet between said units, said sub-pallet conveyor system having atleast five swiveling axes and configured to include said sub-palletcarrying parts of said machine tool, said setup station and saidsub-pallet stocker in a workable area thereof, wherein said sub-palletis used to convey and machine a workpiece.